▎ 摘　　要

It is shown that approximately 2 wt% of graphene in the matrix of a unidirectionally-reinforced carbon fiber epoxy composite leads to a significant enhancement in mechanical properties. Particularly, it is found that the axial stiffness of the composites is increased by similar to 10 GPa accompanied by an increase in axial strength of 200 MPa. X-ray computed tomography and polarized Raman spectroscopy have demonstrated that the graphene is predominately aligned parallel to the carbon fibers axes. Stress-induced Raman band shifts showed that the confined and self-aligned graphene is subjected to high levels of stress during axial deformation of the composite, with an effective Young's modulus of similar to 825 GPa, approaching its theoretical value of 1050 GPa. This behavior has been modeled using the rule of mixtures and shear-lag analysis and it is demonstrated that highly aligned graphene in a constrained environment between fibers gives significantly better mechanical reinforcement than graphene in conventional polymer-based nanocomposites.